Music Composers Unite!

Hi all composers , does anyone knows how to calculate the overtones ( or partials) from a single note ?? I have a vst sonogram that shows me all the frequencies in Hz, but how do I see each frequency in notes , so I can write them down in notation ( as for ex. Gerard Grisey did ) . I have websearched a lot but with no result . Plase help if anyone knows !!! Caj.
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